| 摘要 |
PURPOSE:To enable high accurate machining to be performed reducing vibration and heat generation by arranging a pair of rotors and a stator corresponding to each rotor of mutually different generating output with a predetermined space on the same rotary shaft and switching a motor when the machining is performed and when the rotary shaft is accelerated and decelerated. CONSTITUTION:A superprecision lathe uses a built-in type rotary shaft serving as the main spindle, when it is in stopping, a workpiece is mounted to a chuck 5, thereafter electrifying a stator 8, the main spindle obtains its rotary speed to the required value in a short time. After the main spindle reaches the required speed, the stator 8 is stopped in its electrification, and a stator 9 is electrified. Then the main spindle is rotated by the second motor, enabling a speed to be maintained necessary for machining. Next the stator 9, when the machining is ended, is stopped to be electrified, and the stator 8 is electrified in a direction of generating counter electromotive force. Then the main spindle stops in a short time. Thus by switching the electrification to the first and second motors, the main spindle enables its acceleration and deceleration to be performed in a short time further vibration to be decreased of the main spindle when it performs the machining. |
